Luse R W, Blasko J, Grimm P
Deaconess Medical Center, Spokane, WA 99210-0248, USA.
Int J Radiat Oncol Biol Phys. 1997 Feb 1;37(3):737-41. doi: 10.1016/s0360-3016(96)00576-7.
To present our experience implementing the American Association of Physicists in Medicine (AAPM) Task Group #43 (TG-43) recommendations for 125I dosimetry parameters utilizing two commercially available treatment planning systems.
Single seed point source calculations were performed on two treatment planning systems and intercomparisons were conducted between known points of interest for (a) previously published data on each system, (b) TG-43 data on each system, and (c) hand calculations. Additional calculations and intercomparisons were performed for a typical 35 cm3 prostate volume implant with a prescribed dose of 160 Gy.
Intercomparisons of calculations for single seed point source approximations with previously published data and TG-43 data indicated good agreement between the two systems at a distance of 1 cm. Point source comparisons between previously published data and TG-43 recommendations show a difference in dose of 11% to the 1 cm point. Calculations for a 35 cm3 permanent interstitial prostate implant showed the 160 Gy isodose line pulled centrally toward the seeds 1-2 mm as a result of the 11% change.
It is advisable for physicians, physicists, and dosimetrists to exercise caution when incorporating the TG-43 recommendations for 125I into treatment planning systems. The effects caused by differences in dosimetry parameters need to be understood and accounted for when matching prescribed doses in order to ensure continuity of treatment and clinical results as reported in the current literature.
介绍我们利用两个商用治疗计划系统实施美国医学物理学家协会（AAPM）任务组43（TG - 43）关于125I剂量测定参数建议的经验。
在两个治疗计划系统上进行单粒籽源点源计算，并在以下各已知感兴趣点之间进行比对：（a）每个系统先前发表的数据；（b）每个系统的TG - 43数据；（c）手工计算结果。对一个规定剂量为160 Gy的典型35 cm³前列腺体积植入进行了额外的计算和比对。
单粒籽源点源近似计算与先前发表的数据和TG - 43数据的比对表明，在1 cm距离处两个系统之间具有良好的一致性。先前发表的数据与TG - 43建议之间的点源比较显示，1 cm处的剂量差异为11%。对35 cm³永久性间质前列腺植入的计算表明，由于11%的变化，160 Gy等剂量线向籽源中心方向拉近1 - 2 mm。
在将TG - 43关于125I的建议纳入治疗计划系统时，医生、物理学家和剂量测定师应谨慎行事。在匹配规定剂量时，需要了解并考虑剂量测定参数差异所造成的影响，以确保如当前文献所报道的治疗连续性和临床结果。
